Parameterized method names in generated server code.

Thanks to David Wei for catching this.

Plugin/swiftgrpc.templates/server-session-bidistreaming.swift

@@ -60,7 +60,7 @@ public class {{ .|session:protoFile,service,method }} {
     try self.handler.sendMetadata(initialMetadata:Metadata()) {
       queue.async {
         do {
-          try self.provider.update(session:self)
+          try self.provider.{{ method.name|lowercase }}(session:self)
         } catch (let error) {
           print("error \(error)")
         }

Plugin/swiftgrpc.templates/server-session-clientstreaming.swift

@@ -43,7 +43,7 @@ public class {{ .|session:protoFile,service,method }} {
     try self.handler.sendMetadata(initialMetadata:Metadata()) {
       queue.async {
         do {
-          try self.provider.collect(session:self)
+          try self.provider.{{ method.name|lowercase }}(session:self)
         } catch (let error) {
           print("error \(error)")
         }

Plugin/swiftgrpc.templates/server-session-serverstreaming.swift

@@ -24,7 +24,7 @@ public class {{ .|session:protoFile,service,method }} {
           // we dispatch them to another queue.
           queue.async {
             do {
-              try self.provider.expand(request:requestMessage, session: self)
+              try self.provider.{{ method.name|lowercase }}(request:requestMessage, session: self)
               try self.handler.sendStatus(statusCode:0,
                                           statusMessage:"OK",
                                           trailingMetadata:Metadata(),

Plugin/swiftgrpc.templates/server-session-unary.swift

@@ -14,7 +14,7 @@ public class {{ .|session:protoFile,service,method }} {
     try handler.receiveMessage(initialMetadata:Metadata()) {(requestData) in
       if let requestData = requestData {
         let requestMessage = try {{ method|input }}(protobuf:requestData)
-        let replyMessage = try self.provider.get(request:requestMessage)
+        let replyMessage = try self.provider.{{ method.name|lowercase }}(request:requestMessage)
         try self.handler.sendResponse(message:replyMessage.serializeProtobuf(),
                                       statusCode: 0,
                                       statusMessage: "OK",